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Finding the Fourth Proportional to 1,271.80, 1,908.30 and 947.80

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Solution

The fourth proportional to 1,271.80, 1,908.30 and 947.80 is: 1,422.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,271.80 : 1,908.30 = 947.80 : x
  2. Step 2: Convert to fraction form
    1,271.80/1,908.30 = 947.80/x
  3. Step 3: Cross multiply
    1,271.80x = 1,908.30 × 947.80
  4. Step 4: Simplify right side
    1,271.80x = 1,808,686.74
  5. Step 5: Solve for x
    x = 1,808,686.74/1,271.80
  6. Step 6: Final answer
    x = 1,422.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.